Bats (order Chiroptera = “hand-wing”) are among the most common living mammals. They represent nearly one-fifth of all mammalian species and live virtually everywhere, except in the harshest of polar climates. Most bats are active only during the evening and at night, making their activities mysterious to most people. Bats are among the most important seed dispersers in the tropics and, along with birds, are a major factor in controlling insect populations worldwide.